Retail investors in Northern Rock would be asked to invest about £770 (€1,073) in the company if a Richard Branson-led rescue of the mortgage bank proceeds.
The Virgin consortium's proposals include a rights issue to raise £650 million at 25 pence per share, equivalent to asking Northern Rock's original shareholders to buy about 3,080 new shares, according to calculations.
When the mutually owned Northern Rock Building Society listed in London in October 1997 it handed 500 shares free to each of 885,764 qualifying investors and borrowers, according to its website.
The Virgin consortium's proposed rights issue would result in 2.6 billion new shares being issued, just under 6.2 new shares for every existing Northern Rock share, or about 3,080 shares if such investors still own the 500 shares given in 1997.
Northern Rock would not say how many "small investors" it has, but the figure is widely believed to be well over 100,000.
The consortium has been declared the preferred bidder for Northern Rock, with a promise to repay the British government £11 billion immediately on the sale going through.
The British government has asked the European Commission to approve the aid it has provided to Northern Rock.